The present invention relates to a liquid developer reservoir for a copying machine.
When a liquid developing method is adopted to develop an electrostatic latent image formed on a photosensitive paper after passing steps of a charging and an exposure, a developing period or a time period when the photosensitive paper is dipped in a developing liquid is an important factor to obtain a clean copy. Especially, when the photosensitive paper is driven downward and upward to be dipped in the developing liquid, difference of the developing period between the leading edge and the trailing edge of the photosensitive paper causes a difference of development contrast. To avoid the occurrence of the development contrast difference, it was necessary, in the prior art, to dip the photosensitive paper in the developing liquid of considerably low concentration during a considerably long period necessary for bringing the developing section into saturated concentration. Therefore, it took more than 10 seconds to obtain clean copy in the prior art method. When the liquid developing method of the above-mentioned prior art was adopted to a multicolor electrophotography apparatus, a considerably long period was required to complete a sheet of multicolor image formation, since the developing operation was repeated at least three times.
It is effective to use a toner having a relatively high speed attachment velocity characteristic in order to reduce a necessary time period to perform the developing operation. In this case, the toner located near the surface of the photosensitive paper may be rapidly attached to the photosensitive paper, but the toner concentration will become dilute near the surface of the photosensitive paper. The toner must be supplied to the diluted portion by mechanically stirring or circulating the developing liquid.